On October 10, 2018, the U.S. Department of Energy (DOE or Department) issued a Federal Register notice seeking public comment on the Department’s interpretation of the definition of the statutory term “high-level radioactive waste” (HLW) as set forth in the Atomic Energy Act of 1954 and the Nuclear Waste Policy Act of 1982.
DOE interprets the term “high-level radioactive waste,” as stated in the Atomic Energy Act of 1954 as amended (AEA) and the Nuclear Waste Policy Act of 1982 as amended (NWPA), in a manner that defines DOE reprocessing wastes to be classified as either HLW or non-HLW based on the radiological characteristics of the waste and their ability to meet appropriate disposal facility requirements. The basis for DOE’s interpretation comes from the AEA and NWPA definition of HLW:
- the highly radioactive material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that contains fission products in sufficient concentrations; and,
- other highly radioactive material that the Commission, consistent with existing law, determines by rule requires permanent isolation.
In paragraph A, according to the Federal Register notice, Congress limited HLW to those materials that are both “highly radioactive” and “resulting from the reprocessing of spent nuclear fuel.” Reprocessing generates liquid wastes, with the first cycle of reprocessing operations containing the majority of the fission products and transuranic elements removed from the spent nuclear fuel (SNF). Thus, in paragraph A, Congress distinguished HLW with regard to its form as both “liquid waste produced directly in reprocessing” and “any solid material derived from such liquid waste that contains fission products in sufficient concentrations,” states the Federal Register notice.
In paragraph B, Congress defined HLW also to include “other highly radioactive material” that the U.S. Nuclear Regulatory Commission (NRC) determines by rule “requires permanent isolation,” continues the Federal Register notice. HLW under paragraph B includes highly radioactive material regardless of whether the waste is from reprocessing or some other activity. Further, under paragraph B, classification of material as HLW is based on its radiological characteristics and whether the material requires permanent isolation, states the Federal Register notice.
According to the Federal Register notice, the common element of these statutory paragraphs defining HLW is the requirement and recognition that the waste be “highly radioactive.” Additionally, both paragraphs reflect a primary purpose of the NWPA, which is to define those materials for which disposal in a deep geologic repository is the only method that would provide reasonable assurance that the public and the environment will be adequately protected from the radiological hazards the materials pose.
The terms “highly radioactive” and “sufficient concentrations” are not defined in the AEA or the NWPA. By providing in paragraph A that liquid reprocessing waste is HLW only if it is “highly radioactive” and that solid waste derived from liquid reprocessing waste is HLW only if it is “highly radioactive” and contains fission products in “sufficient concentrations” without further defining these standards, the Federal Register notice asserts that Congress left it to DOE to determine when these standards are met. Given Congress’ intent that not all reprocessing waste is HLW, the Federal Register notice states that it is appropriate for DOE to use its expertise to interpret the definition of HLW, consistent with proper statutory construction, to distinguish waste that is non-HLW from waste that is HLW.
The DOE interpretation is informed by the radiological characteristics of reprocessing waste and whether the waste can be disposed of safely in a facility other than a deep geologic repository. The Federal Register notice explains that this interpretation is based upon the principles of the NRC’s regulatory structure for the disposal of low-level radioactive wastes.
In its regulations, NRC has identified four classes of low-level radioactive waste (LLW) — Class A, B or C — for which near-surface disposal is safe for public health and the environment, as well as Greater-than-Class C (GTCC) low-level radioactive waste for which near-surface disposal may be safe for public health and the environment. This waste classification regime is based on the concentration levels of a combination of specified short-lived and long-lived radionuclides in a waste stream, with Class C LLW having the highest concentration levels. Waste that exceeds the Class C levels is evaluated on a case-specific basis to determine whether it requires disposal in a deep geologic repository or whether an alternative disposal facility can be demonstrated to provide safe disposal. According to the Federal Register notice, the need for disposal in a deep geologic repository results from a combination of two radiological characteristics of the waste: (1) high activity radionuclides, including fission products, which generate high levels of radiation; and, (2) long-lived radionuclides which, if not properly disposed of, would present a risk to human health and the environment for hundreds of thousands of years.
Because the NRC has long-standing regulations that set concentration limits for radionuclides in waste that is acceptable for near-surface disposal, the Federal Register notice contends that it is reasonable to interpret “highly radioactive” to mean, at a minimum, radionuclide concentrations greater than the Class C limits. Reprocessing waste that does not exceed the Class C limits is non-HLW.
DOE interprets “sufficient concentrations” in the statutory context in which the definition was enacted, which is focused on protecting the public and the environment from the hazards posed by nuclear waste. In addition to the characteristics of the waste itself, the risk that reprocessing waste poses to human health and the environment depends on the physical characteristics of the disposal facility and that facility’s ability to safely isolate the waste from the human environment. Relevant characteristics of a disposal facility may include the depth of disposal; use of engineered barriers; and, geologic, hydrologic and geochemical features of the site. Taking these considerations into account, the Federal Register notice states that it is reasonable to interpret “sufficient concentrations” to mean concentrations of fission products in combination with long-lived radionuclides that would require disposal in a deep geologic repository.
Accordingly, under DOE’s interpretation, solid waste that exceeds the NRC’s Class C limits would be subject to detailed characterization and technical analysis of the radiological characteristics of the waste. This, combined with the physical characteristics of a specific disposal facility and the method of disposal, would determine whether the facility could meet its performance objectives and if the waste can be disposed of safely. The waste characterization and analysis process would govern this approach, as well as the performance objectives for the disposal facility established by the applicable regulator, to ensure that it is protective of human health and the environment.
The DOE interpretation does not require the removal of key radionuclides to the maximum extent that is technically and economically practical before DOE can define waste as non-HLW. According to the Federal Register notice, nothing in the statutory text of the AEA or the NWPA requires that radionuclides be removed to the maximum extent technically and economically practical prior to determining whether waste is HLW. DOE has determined that the removal of radionuclides from waste that already meets existing legal and technical requirements for safe transportation and disposal is unnecessary and inefficient, as well as does not benefit human health or the environment. To the contrary, the Federal Register notice states that it potentially presents a greater risk to human health and the environment because it prolongs the temporary storage of waste.
Therefore, under DOE’s interpretation, waste resulting from the reprocessing of SNF is non-HLW if the waste:
- does not exceed concentration limits for Class C low-level radioactive waste as set out in section 61.55 of title 10, Code of Federal Regulations; or,
- does not require disposal in a deep geologic repository and meets the performance objectives of a disposal facility as demonstrated through a performance assessment conducted in accordance with applicable regulatory requirements.
Reprocessing waste meeting either I or II of the above is non-HLW. Therefore, according to the Federal Register notice, such waste may be classified and disposed in accordance with its radiological characteristics in an appropriate facility provided all applicable requirements of the disposal facility are met.
For additional information, see 83 Federal Register 50,909 (October 10, 2018). Interested stakeholders may also contact Theresa Kliczewski at HLWnotice@em.doe.gov or at (202) 586-3301.